Is gravity not actually a force? Forcing theory to meet experiments

Is gravity a result of differences in informational density? Or is this theory …

How are controversial ideas handled by modern science? A common charge leveled against science (generally by those who are unhappy with its conclusions) is that the only way to get funding or continue your research is by going along with the current theories and not rocking the boat. For those who spend their careers in science, this is laughable—it is those who successfully rock the boat who are the most successful. In this article, we are going to look at a manuscript that purports to overturn hundreds of years of accepted ideas about gravity, and use it as an illustration of how controversial ideas are dealt with in modern physics.

It was Isaac Newton who first proposed a universal law of gravitation, where every massive body in the universe was attracted to every other one. This simple law proved extremely powerful, able to explain the orbits of planets and the reason the apocryphal apple fell on his head. However, Newton was never able to explain why gravity worked or what exactly it was. Two hundred plus years later, Albert Einstein was able to offer a more complete description of gravity—one where Newton's laws are a limited case. According to Einstein, gravity was due to the warpage of spacetime by mass and energy; all objects followed straight paths, just on curved spaces.

With the advent of quantum theory over the past 100 years, scientists have been able to develop an elegant mathematical framework capable of uniting three of the four fundamental forces that are thought to exist in the universe. The fourth, gravity, still remains the fly in the ointment, and has resisted unification to this point. Early last year, Dutch theoretical physicist Erik Verlinde published a manuscript to the arXiv that purports to explain why science cannot reconcile all four fundamental forces. According to him, it is simple: "gravity doesn’t exist."

Some background reading

Before we dive into this seemingly unphysical statement, we need to take a detour to discuss some of the ideas from modern physics that form the basis of Dr. Verlinde's argument: black hole thermodynamics and the holographic principle. Black hole thermodynamics was worked on extensively in the 1970s. It's needed in order to reconcile the second law of thermodynamics with the idea of a black hole event horizon. To do this, one has to admit that a black hole must have finite, non-zero entropy. If a black hole has zero entropy, then throwing mass into a black hole would violate the second law of thermodynamics, as the sum total entropy of the universe would decrease by the amount of entropy contained within the mass.

This also demands that, oddly, black holes cannot be purely black. If something has a non-zero entropy, then it must also have a non-zero temperature. This temperature is the temperature of the Hawking radiation that is given off due to the quantum nature of the black hole itself. A simple way to imagine Hawking radiation involves considering the particle-antiparticle pairs that spontaneously form the vacuum fluctuations. If one forms near the event horizon, it can fall in, never to be seen again, while its mate flies off into the Universe. To a faraway observer, the black hole just emitted a particle (even trippier is the fact that the particle that fell in must have had negative energy, and decreased the total energy of the black hole—something that could cause the black hole to evaporate over time).

Leading us further down the (black) rabbit hole are other results of Stephen Hawking's calculations, which fixed the maximum entropy that a black hole can have. Since that's a (quasi) measurement of how much information can be stored by an object, a black hole represents the most informationally dense object possible in the Universe. Surprisingly, the maximum entropy a black hole can obtain is exactly Planck's constant times one quarter of its area in Planck lengths—not its volume, an important distinction. This result implies that every bit of information the black hole can contain (as an Infosphere) is described entirely by its surface, the event horizon.

An extension to this line of surface-focused thinking came in the 1990s, when Gerardus 't Hooft, and later Leonard Susskind, postulated that the universe is a form of a hologram, a lower dimensional object that looks like a higher dimensional one (think of the two dimensional hologram images that look three dimensional). The holographic principle says that all space and time contained within an N dimensional body is emergent and can be described by a completely separate set of physics on the N-1 dimensional surface of the body.

This is one of those mind-bending ideas that float around and form the basis of a not-insignificant portion of modern physics, so I'll try and give a simple example. Imagine the entire Universe is a beach ball, and all physics within it—space, time, matter, energy—is described by the ideal gas law. The holographic principle then states that the entirety of the Universe (the inside of the beach ball) can also be described by a different set of equations that describe only the surface of the ball, the vinyl part itself; as an example, maybe a set of equations linking the surface tension to the area of the ball.

There's a corollary to this (one that will be heavily relied on in a minute): all the information about the Universe (in this case the beach ball) is encoded on the two dimensional surface of the ball. Another analogy I have seen used to describe this is that of a soup can: everything you could know about what is in the can of soup is printed on its label.

Tying this back to the black holes we started with: the holographic principle suggests that everything we could want to know about the interior of a black hole is encoded in some manner on the surface of its event horizon. Since we can never recover information from beyond the veil of the event horizon, everything that can be known about a black hole, and everything that has ever fallen into it, must be represented on the event horizon itself. In fact, in some variants of string theory, this concept resolves the black hole information paradox.

This idea may sound completely abstract (and it is), but it has turned out to be remarkably useful, because it has produced what is called the AdS/CFT correspondence. This uses the holographic principle to show a direct correspondence between problems in what is known as Anti-deSitter space, where gravity is present (a cosmological way of describing the Universe) and problems in conformal field theory in a lower dimensional space where gravity does not exist (used heavily in quantum mechanics). Problems not solvable in one regime (cosmology, the AdS portion) have an equivalent problem that may be trivially solvable in the other (quantum field theory, the CFT portion).

A mind-bending proposal

Dr. Verlinde's proposition is not entirely unique. Others have argued that gravity, instead of being a fundamental force of the Universe, is instead an emergent phenomenon. A good deal of this thinking comes from the fact that the equations that describe gravity (in the Newtonian limit, at least) are mathematically similar to those that describe other emergent phenomena, such as fluid mechanics or thermodynamics. Where Dr. Verlinde goes the next step forward is by arguing for a definite mechanism behind gravity: differences in entropy.

In his freely available manuscript, entitled "On the Origin of Gravity and the Laws of Newton,"—the title seemingly paying homage to Einstein's famous paper whereby special relativity was laid out—Verlinde sets out his case for why gravity is, as he terms it, an "entropic force." The manuscript uses a combination of the holographic principle and black hole thermodynamics to (re)derive the basic equations of motion that Newton presented over 300 years prior.

Verlinde makes extensive use of the holographic principle in his derivations. He works with a thought experiment that assumes one has a holographic screen—one where all the information about what is contained inside of it is encoded as bits on its surface—and asks how it would interact with matter or energy that is being held just outside of it.

To show how Newton's equations of universal gravitation are derived, Verlinde begins with the difference in entropy between a mass M and a spherical holographic screen with entropy S—the information encoded on the screen would describe the emergent space inside, which would be "viewed" as equivalent to a mass M at its center. The attractive force between the the mass and the screen—what we would commonly call gravity—becomes, as Verlinde describes it, an entropic force due to the different informational densities between the two regions.

Not being content to leave it there, Verlinde goes further and rederives Newton's famous second law, F=ma (fun historical note: F=ma appears exactly zero times in Newton's famous Principia). Through that derivation, Verlinde is able to associate acceleration with an entropy gradient. According to his work, a particle at rest will stay at rest because there is no entropy gradient around it. This allows him to identify Newton's potential—the negative of the gradient, which is the acceleration a particle feels—as a potential that "keeps track of the depletion of the entropy per bit."

With such a description, extending the idea further becomes feasible. The entropic potential previously identified is shown to follow the common Poisson equation that describes the distribution of matter about a system. So he concludes that, if temperature and informational density on the holographic screen are chosen properly, then the laws of gravity fall out of this theory in a straightforward fashion.

Up to this point in the manuscript, everything Verlinde has derived applies to non-relativistic cases. How well does such a radical departure hold up when viewed through the lens of relativity theory? Here, Verlinde starts with the general relativistic description of Newton's potential. He then goes on to derive the force required to hold a particle a fixed distance away from a holographic screen, and again is able to derive the commonly accepted equation with force now described by a difference in entropy between the point and the screen. Furthermore, the manuscript lays out a path—but does not explicitly follow it—for one to rederive the full set of Einstein's field equations that form the cornerstone of general relativity using the fact that gravity, in Verlinde's work, is an "entropic force."

The paper is clearly unconventional, but it provides a compelling argument, and backs it up with actual work. Despite the highly controversial ideas it puts forth and the fact that it has not gone through peer review, it has caused some people in the scientific community to sit up and take notice.

Clearly, one paper making extraordinary claims will not be taken as fact until others can replicate the work, or in the case of a theoretical paper such as this, verify it with experimental evidence. A paper published in a recent edition of Physical Review D has attempted to do just that.

Not so fast

Dr. Archil Kobakhidze, a research fellow in theoretical particle physics at the University of Melbourne, points to recent results that may undermine Verlinde's ideas. Kobakhidze acknowledges that Verlinde's work successfully reproduces gravity on the Newtonian scale, and possibly in the more general relativistic sense, but it must also work at the quantum level as well, or it's not going to change modern physics.

Kobakhidze attempts to apply Verlinde's ideas to see if they are in agreement with the results from experiments on ultra-cold neutrons falling in the Earth's gravitational field. Solving the conventional quantum mechanical equations that describe this system give results that are in good agreement with the experiment. Verlinde's paper does not fully explain how to work with microscopic systems in his modified view of gravity, but according to Kobakhidze, enough ideas are present to work it out as homework.

Kobakhidze uses Verlinde's approach to re-derive the wave equation that will describe the energy levels of neutrons falling in Earth's gravitational well. What he finds is that, in contrast to the more conventional equation, there are two extra terms now present. One would appear to account for the relativistic rest energy of the neutron; the other is a form of an extreme suppression of certain parts of the neutron's wavefunction. Both of these additions result in problems for Verlinde's theory.

The first extra term, the relativistic rest energy, would manifest itself as a constant shift in the neutron's energy states (height above the bottom of the well)—this is not seen at all in the experiments. According to Kobakhidze, though, it is the second extra term that really throws a wrench into entropic gravity. The second term, if correct, would significantly change the dynamics of the experiment, essentially causing neutrons to fall through the small hole in the bottom of the potential well. There's no sign of this happening in any meaningful way in the experiment. Thus, Kobakhidze concludes, "we are driven to the conclusion that gravity is not an entropic force."

This is how science works. Ideas are proposed, they are backed up, they are shot down. Over time, it would not surprise me to see Verlinde defend his work. Perhaps Kobakhidze's derivation and its extension to the microscopic case is incorrect. Perhaps Verlinde will revisit his original work to revise how microscopic cases should be handled. Whatever happens, science will move on; time, further arguments, and experiments will be the ultimate arbiter of which drastically different view of reality is correct.

I won't pretend to understand all of what was said in this article, but when they talk about gravity being the difference in entropy between the mass and the screen it seems to be suggesting that "gravity" would be equal at all points on the surface that are of equal distances from said mass. This certainly doesn't seem to be the case for Earth where gravity varies everywhere. I doubt at all points on the surface equidistant from the center the gravity is the same. It could be that other forces are coming into play since everything has "gravity."

Dr. Verlinde also said that the force is cause by the difference in information densities between the mass and the screen. I'm not sure if that's just another way of stating the differences in entropies though. Is he suggesting that the "information" of Earth is contained on its surface?

Or is simply trying to apply his theory/idea to the universe as a whole? The latter seems to make more sense to me since the "screen" for the universe is rather unknown. Though, with the knowledge that the universe is ever expanding that would seem to mean that the "information" of the whole universe is either constantly expanding to match the rate that the screen is expanding or that the information density of the screen of the universe is constantly decreasing (could conceivably be constantly increasing but it seems just as unlikely as it's constantly decreasing). If the latter was happening then wouldn't the difference in information densities between the mass and the screen be ever decreasing, until they actually passed each other going opposite directions, meaning that "gravity" is ever decreasing. The whole idea seems a bit preposterous unless the information never changes and the size of the screen never changes either. Even if they increased at the same rate it couldn't possibly be perfectly even 100% of the time meaning that gravity would fluctuate at all times.

Or am I just spouting total rubbish with my lack of understanding of the material?

I remember being yelled at for comparing gravity to fluid mechanics in college.

I very much like the theory that Gravity is an emergent property. Applause on suggesting the 'emergent' nature of Gravity back when you were in college.

Will be very nice if science can adequately explain Gravity, and make it couple nicely with the other (er) three forces.

I'm glad we live in the stelliferous age of the universe (where stars and galaxies are plentiful), it makes our current Earthly 'energy crisis' look like a tiny problem with relatively easy solutions, compared to a universe at 10^30, or even 10^90 seconds, which has "lost" most of the 'free' energy.

Since Einstein already posited that gravity was not a force but a warping of space-time, why can THAT idea of gravity as a non-force not be used to avoid the "grand force unification" imperative?

again...sorry for the dumb question.

Because that would be lazy/cheating. LOL I believe the real question they are trying to answer is "what in the big bang gave rise to the warping of space time?" Calling it a force or not a force does not give any insight into that problem, unless you have an alternate (testable) theory to back it up.

Since Einstein already posited that gravity was not a force but a warping of space-time, why can THAT idea of gravity as a non-force not be used to avoid the "grand force unification" imperative?

again...sorry for the dumb question.

Because that would be lazy/cheating. LOL I believe the real question they are trying to answer is "what in the big bang gave rise to the warping of space time?" Calling it a force or not a force does not give any insight into that problem, unless you have an alternate (testable) theory to back it up.

But the emergent observed result is a force in both cases... and the article seems to imply that finding a way to call gravity a non-force frees us from having to unify it with the other forces.

So..I hope you can see the origin of my misconception. Why does this way of saying gravity is a non-force free you from unification and not the other way?

I am sure there is more to it. Maybe the entropic explanation has some special attribute that allows us to not need unification. Is this the case? Then what are these attribute(s)?

EDIT: or rather, why does explaining the warping of space this way free us from unification and why did we need to unify the forces without this explanation?

EDIT: The quote in question fro the article: "scientists have been able to develop an elegant mathematical framework capable of uniting three of the four fundamental forces that are thought to exist in the universe. The fourth, gravity, still remains the fly in the ointment, and has resisted unification to this point. Early last year, Dutch theoretical physicist Erik Verlinde published a manuscript to the arXiv that purports to explain why science cannot reconcile all four fundamental forces. According to him, it is simple: 'gravity doesn’t exist.' "

Since Einstein already posited that gravity was not a force but a warping of space-time, why can THAT idea of gravity as a non-force not be used to avoid the "grand force unification" imperative?

again...sorry for the dumb question.

Because it is not an explaination, it is just a different perspective. It is like asking why is that bus moving close to me? and answering, because you are moving closer to the bus. You can restate any force as something affecting the coordinate system instead of something applying within the coordinate system.

Since Einstein already posited that gravity was not a force but a warping of space-time, why can THAT idea of gravity as a non-force not be used to avoid the "grand force unification" imperative?

again...sorry for the dumb question.

Because it is not an explaination, it is just a different perspective. It is like asking why is that bus moving close to me? and answering, because you are moving closer to the bus. You can restate any force as something affecting the coordinate system instead of something applying within the coordinate system.

So Einstein's re-interpretation of gravity was nothing more than a shift of coordinate systems and frames??

Furthermore... what is we find an underlying explanation of EM that does not posit additional forces? then what? why does a force having a non-force based underlying explanation exempt it from the need to unify? And why is there a need to unify anyway? Can we not have a theory of everything without unification? With just... more than one fundamental force "just existing"?

"A common charge leveled against science (generally by those who are unhappy with its conclusions) is that the only way to get funding or continue your research is by going along with the current theories and not rocking the boat. For those who spend their careers in science, this is laughable—it is those who successfully rock the boat who are the most successful."

Those who "successfully rock the boat" are few and far apart, and they most likely didn't get funding for the stuff that rocked the boat. Until the rocking was well under the way, anyway. Those who spend their careers in science very probably have not rocked the boat or discovered anything revolutionary. The structure around science is geared towards mundane advances and managerial lead scientists (who are successful mostly in gathering a team around them and producing constant work products, not in doing science themselves, or in producing singular revolutionary ideas).

I'm not laughing. In my opinion, a significant part of this is due to the peer review process itself. There is not enough (or any) incentive to spend time thoroughly reviewing other people's work. Papers that appear to be solid at first glance (based on accepted ideas and that have results that are prima facie logical) have a much better chance of being accepted than wild thought experiments or first drafts of something revolutionary. (Ok, some have succeeded in selling or marketing their results by suggesting all kinds of links to bigger and more interesting questions, even if their links are tenuous at best and their results very limited and partially known already. Again, you could say that the reviewer didn't do his/her job thoroughly enough, but that may be harsh. Many such cases exist in artificial intelligence.) There is a reason this work was not peer reviewed, just as Einstein's work in 1905 was not peer reviewed either. Not that this work is equivalent. But a nice thought experiment, in any case.

You are not banned from doing or publishing what you want, but you'd better get funding from something more mainstream and be ready for a frustrating fight. On the other hand, there are a lot of people around who think they have discovered something very interesting, and actually have not. And they seem to be completely blind to this. If the goal is to produce revolutionary ideas, you probably would have to accept a large number of spectacular misses for a single working idea. But how can you get funding if your ideas will with high probability turn out to be a spectacular misses?

Edit: On the same note, to really comment on the work in question, you would have to spend a lot of time on it. And if actual reviewers can't find enough time, how could we?

Since Einstein already posited that gravity was not a force but a warping of space-time, why can THAT idea of gravity as a non-force not be used to avoid the "grand force unification" imperative?

again...sorry for the dumb question.

The problem is that, in the cases of quantum mechanics/Standard Model and Relativity, the two theories can not mathematically co-exist. Applying Relativity to quantum mechanics (or vice versa) results in obviously incorrect answers (particles suddenly appear to have infinite mass, etc) and at least one of the two MUST be partially incorrect.

For a "non-force" description of gravity to work and relieve the unification requirement, it must be applicable to quantum mechanics as well astronomical bodies. This is why the experimental data in the Phys Rev paper is so interesting - it applies the theory to a quantum mechanical problem and finds that it doesn't adequately explain the behavior.

Since Einstein already posited that gravity was not a force but a warping of space-time, why can THAT idea of gravity as a non-force not be used to avoid the "grand force unification" imperative?

again...sorry for the dumb question.

The problem is that, in the cases of quantum mechanics/Standard Model and Relativity, the two theories can not mathematically co-exist. Applying Relativity to quantum mechanics (or vice versa) results in obviously incorrect answers (particles suddenly appear to have infinite mass, etc) and at least one of the two MUST be partially incorrect.

For a "non-force" description of gravity to work and relieve the unification requirement, it must be applicable to quantum mechanics as well astronomical bodies. This is why the experimental data in the Phys Rev paper is so interesting - it applies the theory to a quantum mechanical problem and finds that it doesn't adequately explain the behavior.

Aah... so Einstein's non-force approach was incompatible with QM... an entropic derivation held the promise of being compatible with QM. Is this correct?

Since Einstein already posited that gravity was not a force but a warping of space-time, why can THAT idea of gravity as a non-force not be used to avoid the "grand force unification" imperative?

again...sorry for the dumb question.

The problem is that, in the cases of quantum mechanics/Standard Model and Relativity, the two theories can not mathematically co-exist. Applying Relativity to quantum mechanics (or vice versa) results in obviously incorrect answers (particles suddenly appear to have infinite mass, etc) and at least one of the two MUST be partially incorrect.

For a "non-force" description of gravity to work and relieve the unification requirement, it must be applicable to quantum mechanics as well astronomical bodies. This is why the experimental data in the Phys Rev paper is so interesting - it applies the theory to a quantum mechanical problem and finds that it doesn't adequately explain the behavior.

Aah... so Einstein's non-force approach was incompatible with QM... an entropic derivation held the promise of being compatible with QM. Is this correct?

Correct. . . ish. For the first statement - exactly. Relativity is completely at odds with QM, and any new approach to gravity (or QM for that matter) has a shot at being compatible.

QM doesn't actually require unification, but lots of physicists and mathematician think that all the forces should unify and be different manifestations of a single underlying framework. Right now, the framework for gravity is fundamentally different than the other 3 forces, but we don't know why. Physicists FEEL like that shouldn't be the case. At the very least, the correct description of QM and the correct description of gravity should be compatible with each other whether or not gravity is a fundamental force or an emergent phenomena.

EDIT - In a weird coincidence, I was reading through some of Nature's recent coverage of Maxwell's 150th birthday and their editorial on unification this morning on the metro. It's all great, fairly accessible reading, and provides a historical perspective. Maxwell kicked all of this stuff off by showing magnetism, electricity, and light were all the same thing. We've been slowly adding to the list since then. http://www.nature.com/news/2011/110316/ ... 1286a.html

Guys like this are also trying to explain TIME away since they also can't find Tachyons or whatever, that it itself does not exist... Come on, Mister Wizard wanna-be, remember that "Evidence of absence, absence of evidence thing?"

Simply put, Gravity might be and Time is quite clearly written on the "Sub - Planck" pattern of reality. A realm that even a far future science might have a nightmare of a time trying to explore.

That would explain, and quite simply, why individual atoms/electricity, etc. aren't noticeably affected by gravity but massive larger objects behave in relation to it. The "Space/Time" material the universe is in is thus distorted by gravity, essentially excess information attracting more information up to the theoretical 11111---infinity range of a 'black hole' that then gets 'fractioned' to prevent a 'crash' in the space/time program. The space/time bend IS gravity and likewise by definition IS time...

Heh, just made a statement there; That any 'information' going into a black hole IS destroyed. Kind of like when I played with a magnet and an old 5" floppy disk back when... Ran it through a scandisk and every byte in every sector was "1" all 128K... Likewise a black hole would compress things to pure base matter (deeply compact fragments/degenerate matter) but at the same time it'd still be much bigger than the substrate (like the disc's material) it's written on.

Though, with the knowledge that the universe is ever expanding that would seem to mean that the "information" of the whole universe is either constantly expanding to match the rate that the screen is expanding

that sounds interesting, depending on the definition of "information" (which I don't know because I am nowhere near having learned any of this). If, by thinking about stuff, we come up with things that weren't initially part of the design of things, does that mean that we have added information by making it up? And do we (among other sentient beings) therefore directly contribute to the surface expansion of the universe?

Also, does that mean that fundamentally and not just philosophically, Descartes had it right all along?

For example, a detector with the mass of Jupiter and 100% efficiency, placed in close orbit around a neutron star, would only be expected to observe one graviton every 10 years, even under the most favorable conditions. It would be impossible to discriminate these events from the background of neutrinos, since the dimensions of the required neutrino shield would ensure collapse into a black hole.

Is he suggesting that the "information" of Earth is contained on its surface?

Hmm, on a different tack, most of the knowledge we have about Earth's structure is actually obtained by observations we make while on its surface. This includes the way the surface reacts during earthquakes (how seismic waves reach different points on it), what minerals are present on the surface and the behavior of the Earth's magnetic field. To come full circle: Earth's mass can be calculated from its gravity, which is here considered entropic...

I might be a bit late to this party, but there's a lower level unification that needs to take place beyond the Grand Theory of Everything (unless what I'm about to describe is the GTE. Its been a while since I studied physics)

QM and relativity both describe how stuff behaves. But they don't agree. Using QM for planets gives wrong answers and using Relativity for quarks gives wrong answers too. But its the same system on different scales, so if either theory is right, you should be able to use it across all scales.

Which means neither is quite right. So a tweaking of one or both might well bring them closer to agreement. When we have a model that works on extremely large AND extremely small scales, and everywhere in between, it'll be a fair bet we've got it right.

There is a very strong encouragement in the system to do your research within a popular theoretical framework. It is easier to get funding in the first place, and furthermore, it will give you more citations and raise your H-index, making it easier for you to get funding later. If you want to be a scientist today, this is the game you must play.

Using an arXiv article is a strange way to argue that the scientific process encourage publication of controversial theories. The scientist who submitted it will get exactly zero scientific credit within the system for the article, as arXiv isn't peer reviewed. Even citations won't count. I'm amazed anyone bothers. I can only imagine there are still places where the old tenure system is still in effect, and researchers thus still have some remains of academic freedom left.

It is true that if you somehow manage to lead a Kuhn paradigm shift, you will get zillions of citations and be set for life. But that happens approximately once a generation.

There is systemic faults in the scientific process as it exists today. It is still better than anything else we have. But the fact that some people abuse the existence of these systemic faults to defend bonehead theories should not stop us from acknowledge that the faults exists.

We can do better. I just have no idea how. The old tenure system had its own faults.

I might be a bit late to this party, but there's a lower level unification that needs to take place beyond the Grand Theory of Everything (unless what I'm about to describe is the GTE. Its been a while since I studied physics)

QM and relativity both describe how stuff behaves. But they don't agree. Using QM for planets gives wrong answers and using Relativity for quarks gives wrong answers too. But its the same system on different scales, so if either theory is right, you should be able to use it across all scales.

Which means neither is quite right. So a tweaking of one or both might well bring them closer to agreement. When we have a model that works on extremely large AND extremely small scales, and everywhere in between, it'll be a fair bet we've got it right.

I might be a bit late to this party, but there's a lower level unification that needs to take place beyond the Grand Theory of Everything (unless what I'm about to describe is the GTE. Its been a while since I studied physics)

QM and relativity both describe how stuff behaves. But they don't agree. Using QM for planets gives wrong answers and using Relativity for quarks gives wrong answers too. But its the same system on different scales, so if either theory is right, you should be able to use it across all scales.

Which means neither is quite right. So a tweaking of one or both might well bring them closer to agreement. When we have a model that works on extremely large AND extremely small scales, and everywhere in between, it'll be a fair bet we've got it right.

What you describe is exactly what I was trying to, and apparently failing to, describe.

The general assumption out there is that our description of QM is largely correct and that the problem lies mainly with gravity - this is why so many theories focus on changing the conception of gravity. There are two approaches to solve the problem. 1. Treat gravity as a fundamental force but get it to play nicer with the other 3 fundamental forces (this can happen by adding new particles, modifying existing particles, etc.). Most theoreticians believe this will "unify" the forces and any successful theory will necessarily explain large scale stuff (planets) as well as fit in with a modified version of the Standard Model. 2. Make gravity an "emergent phenomena" that arises from other, more fundamental forces. In this case, it should be applied to the quantum world without throwing up infinities all over the place, and it should match our astronomical observations as well (holographic principle and string theory are two examples of this type of work).

Check out the link to the nature article I posted above for a much higher level and more precise discussion of this.

"How are controversial ideas handled by modern science? A common charge leveled against science (generally by those who are unhappy with its conclusions) is that the only way to get funding or continue your research is by going along with the current theories and not rocking the boat. For those who spend their careers in science, this is laughable—it is those who successfully rock the boat who are the most successful. In this article, we are going to look at a manuscript that purports to overturn hundreds of years of accepted ideas about gravity, and use it as an illustration of how controversial ideas are dealt with in modern physics."

A very interesting book on the subject is "The Trouble With Physics" by Lee Smolin - where he is writing on the fact that string theory is treated be-all end-all of physics theories and if you want to approach theoretical physics from a different perspective you are hosed as far as funding and even people listening to you.

This is an example of how treating time as a real physical quantity has really screwed up science. Time does not exist. It is a mere human perception of cause and effect. Because time does not exist, general relativity describes the behavior of SPACE, not "spacetime", and a geodesic in SPACE is a non-accelerating world-line through SPACE, which has an ever changing dimensional structure due to localization of mass and/or energy. Thus, what we perceive as the "force of gravity" is really a local change in the structure of space. Were we to describe the structure of space appropriately, the transformations involved would cancel out accelerations and "forces" due to "gravity". Einstein got close to this notion, that gravity does not generate "force", as such, but represents an object following a geodesic through "spacetime", but the concept was muddied by the insistence that time must be incorporated into the math.

Matt Ford / Matt is a contributing writer at Ars Technica, focusing on physics, astronomy, chemistry, mathematics, and engineering. When he's not writing, he works on realtime models of large-scale engineering systems.